Four suicide bombers belonging to three different Al-Qaeda associated groups were present in Rawalpindi and Islamabad, waiting to strike during the elections, an intelligence agency disclosed.

''Austere vigilance is required to thwart any suicide attack or terrorist act planned by the extremist outfits,'' The News reported today while quoting from excerpts of a letter sent by the intelligence agency to law enforcement personnel.

Sadiq Al-Abadi, a Bajaur tribal agency-based Al-Qaeda activist, has sent a suicide bomber to target a political personality on or before the general elections, a reliable source quoting the letter warned.

Sufian al-Yamani, based in the northern areas, has also planned to hit an unknown political personality, the source disclosed on the basis of the agency report.

Two youths, aged between 18 and 20, are said to be in the twin cities of Rawalpindi and Islamabad driving a black Toyota Corolla bearing Karachi registration number to hit their target, the source revealed.

Maulvi Faqir Hussain's group, associated with a banned militant outfit, has sent these two suicide bombers.

Meanwhile, the law enforcing agencies have taken stringent measures in view of the warning issued by the intelligence agency.